no.  16- 25 


i 


XI  E)  RAR.Y 

OF   THE 

U  N  I  VER.SITY 

Of    ILLINOIS 

666 
tio.  16-23 


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UNI\  KRSITVOF  ILLINOIS  BlLLl.riN 

I  ssr  i:  I)    w  i:  i:  k  i.\ 

Vol.  XI.  Jl  1.^    (,,    1VM4.  N,..  4S 

[Kntereii    as    secDiul-cIass    mattir    Dicciiilicr    11,    1912,    at    the    post    office    at 
Urbana,   Illinois,   uiulir  tl»c  Ait  of  Aujjust  24,    1912.] 


BULLETIN  No.  21 

DKPAR'rMKN'l-  OF  CI:R.\MIC\S 

R.   T.    STl'LL,    Acting  l)iriit..r 


DEFORMATION  TEMPERATLRES  () 
SOME  PORCELAIN  GLAZES 

in' 
R.   T.  STULL  AND  W.   L.    HOW  AT 


A  TYPE  OF  CRYSTALLINE  GLAZE 
AT  CONE  3 

c.  c.  RANI)  .ANH  H.  (;.  sriu  Rl.rilT 


I'L'HLisnKi)  in    iHi:  rxn  irsiia'  or  Illinois,  i  rilwa 


1913-19  14 


^^^J1  1JI5 


AiitliDiizcl    Ii.|)iint    fr..ii.    \..li \\l.    IDU.   Truiisiiclimis   Aiiii-rit-uii   (  cruiiiic   S.Kii-l» 


DEFORMATION   TEMPERATURES   OF   SOME 
PORCELAIN  GLAZES 

H.   T.    Srn.L    AND    W  .    I,,    now  AT.    IKUANA.    IM,. 

The  Liioiip  of  gla/.c's  studied  foiiipi'iscs  ten  lim-i/ iiit;il  series 
desiuiuitctl  hy  Icttci-s  fi-oin  A  to  .1.  cacli  sci-ics  iM)ii>i->tinir  4»f  ten 
nieiiihci-s.  The  ^roup  of  one  liiiiidi-t'd  niciiihci-s  (-{nci's  tlic  f(»|. 
lf)\\iiii:-  limits  i-cpi-csciitcd  hy  the  \'nnv  ciinicr  «rl;i/cs : 

TABLE     I— FORMULA    OF    CORNER    GLAZE3 


GLAZB 

K„0 

CaO 

A'=0. 

SiO. 

A-l        

0 .  :\ 
0 .  :> 

O.T 
0.7 
0.7 
0.7 

0.40 
0.40 
0 .  85 
0.85 

2  0 

A-10        

f)   5 

T-1          

2  0 

T-10    

6   5 

TABLE    II— BATCH    WEIGHTS 


BKAMIY- 

Wl.NE 

FELIibP.\R 


V.sv.  No. 

20      BALL 
CLAY 


.\1,(0H), 


A-l 

A-10 

J-i 
J-io 


167.4 
167.4 
167.4 
167.4 


70.0 
70.0 
70.0 
70.0 


1 2 . ;» 

12.9 
12.9 
70.9 


12.9 
12.9 
12.9 
70.9 


270.0 
216.0 


ro.2 


Different  inenilx'i's  in  the  ;^i"oup  wcw  made  1)\"  molecular 
l)lendin<i-  of  the  four  e.xti-eiiies.  Tliese  were  apidied  to  Itisipie 
wall  tile,  .set  in  safrgers  in  a  down  draft  kiln  and  Iturned  to  eone 
!)  in  40  hours. 

Cones  were  also  made  Ifnm  the  jrlazes  and  theii-  deforma- 
tion temperatures  determined  in  a  platinum  resistance  furnaee. 
the  temperatures  bein^  measured  hy  a  platinum.  |)latinum-rhod- 
iuiii  tliennocouple  and  a  Leeds-Xorthiup  direct  leadiii'^'  [xiteii- 
tiometer.   faeeurate  to  Il^C). 


4  DEFORMATION    TEMPERATURES   OF   GLAZES 

The  time-temperature  curve  followed  in  all  determinations 
is  shown  in  Fig'iire  1.  The  temperature  was  raised  to  1200 'C. 
in  120  minutes.  Beyond  this  the  te:nperature  rise  was  2io  de- 
crees per  minute.  A  number  of  deformation  tests  made  on  du- 
plicate Seger  cones  gave  the  following  results:  cone  4— 1212' C. 
cone  6— 1255=C.,  cone  8— 1290=C. 

Deformation-temperature  readings  were  made  on  two  or 
more  cones  of  each  glaze.  The  variation  was  rarely  over  5  =  C., 
and  in  the  majority  of  tests,  duplicate  cones  gave  the  same  tem- 
perature readings. 

TABLE    III  — DEFORMATION    TEMPERATURES    COVERING    THE     LIMITS 


0.3  KcO 
0.7   CaO 

'    0.40  to  0.85  .\1:0..      :      2.0  to  6.5  SiOr: 
1 

1         1         1         1         1         i         1         1          1          1 

1        2l3        4|5l6        7|8|9jl0, 

MOLSCCLES 
AlA 

T 

.  1277  1246 

1232  1235  1247  1252  1248  1260  1267  1265 
:228  1230  1240  1235  1245  1247  1250  1252 

0.85 

i 

.  1275  1240 

0.80 

H 

.  1272  1245 

1232  1230  1230  1232  1235  1235  1245  1245 

0.75 

G 

.  1272  1240 

1228  1228  1232  1232  1233  1237  1235  1247 

0.70 

F 

.  1267  1238 

1225  1225  1225  12251228  1235  1235  1245 

0.65 

E 

.  1232  1225 

1225  1222  1220  1225  1228  1235  1245  1245 

0.60 

D 

.   1230  1225 

1225  1227  1230  1230  1240  1245  1248  1252 

0.55 

C 

.   1232  1228  1228  1228  1228  1230  1240  1248  1252  1255 

0.50 

B 

.  1235  1230  1228  1233  1235  1245  1254  1252  1257  1270 

0.45 

A 

.  1232  1232  1240  1245  1245  1255  1255  1268  1272  1277 

1           i 

0.40 

M 

LECCLES 
Si0„ 

III                     I'll 
2.0    2.5|   3.0    3.5l  4.o:   4.5|   5.0'   5.5|  6.0    6.o' 

!              !       :       '       '       '              ' 

The  average  temper:iture  readings  for  two  or  more  cones  of 
each  glaze  of  the  group  are  given  in  Table  III.  The  results  of 
the  burn  and  the  iso-deformation  lines  are  represented  graphi- 
cally in  Figure  2,  the  deformation-temperature  being  indicated 
in  degrees  centigrade  on  each  line. 

The  RO  is  constant  for  all  glazes.  The  molecular  variations 
of  SiOj  are  plotted  along  the  abscissa  and  the  molecular  varia- 
tions of  Al.,0..  on  the  ordinate. 


DKFOKMATlUN    TK.Ml'KKATl  Kl  S   OF   OLAZtS 


^  3ifaLWt/3cJIV^J. 


6  DEP'OKMATION    TEMPERATl'RES   OE   GLAZES 

In  the  lower  right  corner  are  the  devitrified  ghizes  between 
the  limits : 

RO,  0.4  ALO,,  5.0  SiO, 
RO,  O.4ALO3,  6.3  SiO, 
RO.  O.6ALO3,  6.5  SiO, 

In  the  h)Aver  portion  of  the  devitrified  area  the  glazes  were 
crazed.  In  the  center  of  the  field  are  the  bright  glazes  which 
were  considered  matured.  Bright  glazes  which  were  crazed  are 
found  in  the  lower  left  corner  within  the  limits : 

RO,  0.4AL,O3.  2.5  SiO, 
RO,  O.4AUO3,  2.0SiOo 
RO,  0.5  AlA,  2.0  SiO, 
At  the  left  of  the  field  a  small  group  of  matured  mats  are 
found  between  limits : 

RO,  0.55  AL.O^,  2.0  SiO, 
RO,  0.70  ALO3,  2.0  SiO, 
RO,  0.65  ALO.,,  2.5  SiO, 

In  the  upper  i)art  of  the  field  the  glazes  wei'e  uiuler  fired. 

The  ditf'erence  between  max  and  iiin  deformation  tempera- 
tures is  57° C,  the  softest  one  deforming  at  1220^0.  having  the 
formula,  RO,  0.6  ALO,,,  4.0  SiO,.  The  member  at  the  upper  left 
corner  (RO,  0.85  ALO.,,  2.0  SiO.)  and  the  one  at  the  lower  right 
corner  (RO,  0.4  ALO,,,  6.5  SiO,)  deformed  at  the  max  tempera- 
ture 1277°  C. 

Each  horizontal  series  may  be  considered  as  being  com- 
posed of  the  components,  glaze  a.nd  SiO..  The  broken  line 
CD  passes  through  the  deformation-euteetic  of  each  of  the  ten 
glaze — SiOo  series.  In  a  vertical  direction,  consider  each  series 
made  up  of  glaze  and  ALO3,  the  dotted  line  EF  represents  the 
deformation-euteetic  axis  of  the  ten  glaze— ALO.,  series. 

These  two  axes  (CD  and  EP)  cross  at  the  point  of  lowest 
deformation  temperature  (group  eutectic).  Its  deformation 
temperature  is  ten  degrees  higher  than  the  indicated  tempera- 
ture of  Seger  cone  4.  The  glazes  whose  formulae  correspond  to 
cones  4,  5  and  6  deformed  at  1228" C,  1240° C  and  1245° C  re- 
spectively. 


DEl-'ORMATIOX    THMPERATIRKS   OK   (ihA'AKS 


Tlie  line  AB  is  the  hip-h  ^'loss  axis  plotted  aceording  to  the 
appcai-aiiee  of  the  srlnzed  trials.  The  }rh)ss  axis  follows  roughly 
parallel  to  the  g:laze-SiO..  deforniation-etiteetie  axis  up  to  the 
iiroup  eiitectic.     Beyond  this  point  it  deflects  and  follows  along 


Me>i.ecaL£s 


CO/^£  A'//Vf  BUffN 


CaAfSTANT\ 


f  .3/^0 


./C0O 


psy/r/?/F/£P 
c/PAzeo 


psyiTffiFieo 


the  glaze- ALO3  deformation-eutectic  axis.  The  group  deforma- 
tion-euteetic  lies  near  the  center  of  the  field  of  best  glazes,  and 
the  quality  of  the  glazes  decreases  in  all  direction  away  from 
this  eutoctic  point.  The  general  formulae  of  the  best  glazes  as 
shown  bv  the  ti-ials  are: 


DEEOfiMATIOX    TE:\IPERATURES    OF   GLAZES 

E.O-0.60  ALO3  4.0  SiO,  Deformation  temp.  =  1220  =  C. 

RO-O.55ALO3  3.5  SiO,  Deformation  temp.  =  1227°C. 

IIO-0.55  ALO3  4.0  SiO,  Deformation  temp.  ==  1230^C. 

EO-O.6OAI0O,  3.5  SiO,  Deformation  temp.  =  1222°C. 


T/?AN3.  ^M.  Cf/?.  30C.  yot.  X^/ 


3 TOLL   &  HOl^/AT 


3e>  4Z 

MOL£CCi.£S         3,0, 


30t//VO 
C/?AZeD 


The  ditferenee  between  tlie  deformation-ten] peratures  of 
tlie.se  glazes  and  the  temperature  to  which  they  were  fired  (cone 
9)  is  80^ C  to  90" C,  or  a  difference  of  4  to  4V,  cones.  For  the 
purpose  of  comparison  the  iso-deformation  temperature  lines  are 
plotted  on  the  field  of  porcelain  glazes  burned  at  cone  11  and 


DEFORMATION    TK.MI'KHATl  KKS   OF   OLAZKS  9 

l»i-cvi(iusly  ri'portfd.'  I-Muuk'  ^1.  Tin'  liiirli  irluss  ;ixi.s  C^'l'  lies  tn 
the  riurht  of  the  glaze-SiO.  (Miti-ctic  axis  ami  crossos  the  yrlaze- 
ALO;,  euteetif  axis  eiose  to  \hv  ciitcftif  luciiiltfi-  of  th*-  jrroijp. 
The  best  glazes  in  this  «rroup  are  foinid  in  close  pi-dximity  t<»  the 
group  euteeti*'.  the  saiue  as  in  tlie  cone  :•  Imni.  Not  only  does 
the  group  eutwtie  lie  near  the  eenter  of  the  are;i  of  hest  glazes, 
but  it  is  also  located  at  a  safe  distance  away  fi-oni  devitrili«'ation, 
cra/inu,  matiiess  and  innnatuiity. 

t  rraniic    I.almratnrifs, 

rniversitv    of    Illiiiuis. 


'  liitliifiiccs    of    variaMe    Sibca    and    Aluiniiiu    on    I'orcclain    (;la/.rs    of    Constant    RO, 
Triiii.t.   Amer.  Cer.  Soc,  Vol.   xiv,  pp.   62-70. 


A  TYPE  OF  CRYSTALLINE  GLAZE  AT  CONE  3 


C.  C.  RAND  AND  H.  G.  SCHURECHT,  URBANA,  ILL. 

The  glazes  under  consideration  are  of  a  type  designed  to 
mature  about  «one  3  to  4.  The  ALO.  is  maintained  constant 
throughout  at  .05  equivalent  and  is  introduced  as  Pikes  No.  20 
English  liall  clay.  In  general  the  group  resembles  Worcester's^ 
best  raw  clay  glaze.     ITis  formula  was 

0.331/3  Na,0         )       0  03A1O  (  1-60  SiO, 

0.662/3  ZnO  (       - -^'^  ^-'  1  0.20  B,03 

He  concludes,  however,  that  .05  ALO.,  generally  seems  the  most 
favorable  and  that  many  German  formuhp  call  for  this  amount. 
A  group  of  36  glazes  was  made  with  a  view  to  determine  the 
effect  of  varying  ZnO  against  XaJ)  along  the  ordinate,  and  rutile 
against  flint  along  the  al)scissa. 


/=/o./ 


.OSCaO 


£ 
D 
C 
S 


^SZ^O>  jo3^0j  \o.S770^ 


The  arrangement  of  the  grou})  with  the  formulae  of  the  four 
cornei-s  are  shown  in  Fig.  1,  the  vertical  series  being  designated 
by  numbere.  the  horizontal  series  by  lettei"S. 

Two  frits  of  the  following  compositions  were  used : 

No.  1 
0.25  Na,0    \ 

0.70  ZnO     1 0.30  B.Og    '      1.4  8iO, 
0.05  CoO 


-  Vol.    X    Trans.    Amcr.   Cer.   Soc,   p.    loO.      Function   of   .\Iumina   in  Ciistallino    Glaze. 


C'KVSTAI.l.INi:  <  LAZi:    AT   (  UNK   '^  11 

No.    2 

0.45  ZiiO     Ui.:iO  IV.o,    ;     1.4  SiO, 
O.Of)  ('<)()     I 

Tlu'Sf  \V(M'('  cju'li  iiitiiii.Mlcly  iiiixril  ••iiitl  ^nuiii.l  in  s!ii;ill  luill 
iiiill.s.  i"\i,s('(l.  (|ii<Mi('hc(l  ill  wMlcr.  tli'ii-.l  .iikI  irntniKl  to  pass  80 
iiicsh  sieve. 

Tile  four  corner  L-'ia/es  were  Lrrouml  wet  until  they  pa.s.se(l 
ll'ii  iiiesli  sieve,  and  the  I'eniainiii'^-  <:la/.es  Mended  from  tlieui  in 
nioleeulai-  pr<iportions. 


/ 

^ 

■\ 

/ 

V 

^ — , 



■^ 

/ 

-- 



^ 

l... 

— 

^   M 

N   600 
\ 

/ 

/ 

1 

r-^ 

1?  300 

— 1 

i 

1 

L 

1 

1 

/ 

' — : 

- 

»•    -i 

" 

^    i 

s 

7//7 

' 7 

»//7 

J ? 

■3 

? 7 

t"'  > 

^     l 

*"      /< 

*       ' 

7        M 

' 

'   • 

The  jilazos  were  applied  to  t\vo  sets  of  l)iscuit  tile  by  dip- 
ping;, and  burned  to  eone  :{  in  T)  hour.s  in  a  round,  down-draft, 
open-fired  oil  kiln.  The  fires  were  i)ut  out  when  the  finishing 
temperature  wa.s  reached  and  the  kiln  allowed  to  e<M>l  with  the 
damper  elostnl. 

The  results  were  not  satisfactory,  as  only  a  few  crystalliuQ 
patches  appeai-ed.  These  patches  increased  noticeably  a.s  the  con- 
tent of  ZnO  increased.  Ilii-h  ZnO  also  appeared  to  irive  a  deeper 
blue  as  w(.id<l  l>e  expected.      V.  '■'>  sli<iwei|  the  most  crystallization. 


12 


CRYSTALLINE  GLAZE  AT   COXE  3 


I 
5 


I 


X 


^ 


^ 


> 


^ 


^i 


^^4^1^  C^  ^ 


CRVSTAI.I.lXi;  (iLAZK  AT  CONK  .'i  13 

The  fiiilmv  to  ol)taiii  Lr«M)d  results  \va.s  uttiihiited  to  too  rapid 
(HM^ling,  t-oo  thin  co^itiutr  of  the  irlaze.  and  i)erhai)s  slight  uiidor 
t)iii'iiiii<r. 

Next  two  sets  of  trials  were  dipjjeil,  eai'e  heiiiir  t^lkeu  to  ob- 
tain a  thiek  eoatiiiir  of  the  fjlaze.  and  burned  in  the  same  kiln  t« 
eone  4.  folIowiiiL;'  the  heatiuir  mid  eooliuLr  curve  shown  in  Fi<;ure 
2.  The  pyrometer  showed  a  teiiii)ern1ui'c  of  1170  (',  when  oone 
4  went  down. 

Fi'oni  a  ei-ystalli/.ation  standpoint,  the  i-esults.  Ki^'.  3,  were 
hi'^ddy  satisfaetory.  Kvery  jilaze  showed  a  lai-i^*-  number  of  crys- 
tals and  in  many  eases  was  a  solid  mass  of  crystals  of  varyin«( 
sizes.  The  vai'iation  of  ZiiO  and  Xa^.O  seems  to  have  little,  if  any, 
effect  upon  either  crystallization  or  color. 

Increase  in  TiOo  has  a  marked  effect  upon  both.  As  TiO„ 
increase<i  the  crystals  became  smaller,  and  more  nnin«  imus,  most 
of  the  hiofh  rutile  glazes  consi.sting  of  a  mass  of  small  interlocking 
crystals.  At  0.0  TiO.  and  at  0.1  TiO.,  a  good  blue  color  is  shown, 
but  fixnn  0.1  TiO^  up,  the  blue  is  partially  and  in  some  cjus(«  al- 
most totally  absent.  Bronze  patches  are  (piite  pronnnent.  due 
possibly  to  iron  impurities  in  the  rutile. 

The  two  sets  of  trials  are  very  ncai'l\'  ideiitieaj.  (JIaze  K  '.i, 
with  the  foi-mula 


0.30  Na.O 
0.65  ZnO 
0.05  OoO 


0.05  Al.,(),   J     1.8  SiO, 
0.80  H.,0..     I     0.2  TiO., 


aiiviin  appears  to  contain  the  most  crystals  and  for  this  reason 
was  selected  as  the  glaze  to  use  in  making  di-aw  trials  with  a  view 
to  noting  different  stages  of  crystallization. 

The  glazes  were  dipped  and  burned  in  the  same  manner  as 
before,  a  number  of  ti'ials  of  K  3  being  jjlaced  where  Ihey  could 
l)e  drawn.  .  One  was  drawn  at  the  finishing  point,  and  one  evei-y 
20  as  the  cooling  progressed.  The  thii-d  trial  drawn  showed 
crystals  around  the  edges.  The  amount  of  crystallization  in- 
creased steadily  for  four  trials.  The;  lU'.xt  ti'ial  at  1030"C  showed 
a  very  great  iiu'rease,  the  glaze  consisting  <d"  a  mass  of  crystals. 
It  is  posible  that  this  is  du<'  to  the  crystallization  of  an  eutectic. 


14 


CRYSTALLINE  GLAZE   AT   CONE  3 


That  is,  the  oompound  forming  the  crystals  shown  fimt  continued 
crystallizing  out  until  the  melt  reached  the  composition  of  the 
eutectie  mixture,  when  the  whole  mass  crystallized.     (Fig.  4.) 


TffA/vs.  Am.  C£/^.  Soc.  l^o/L .  X)//    /^/o.^.      /^AA/c  &  Sc^u/f^c^r 


//70''C 


/OYCC 


/05O°C 


/OJO°C 


/o/o  °0 


One  set  of  trials  was  i)hu>ed  on  edge  in  this  last  burn.  They 
failed  to  show  as  much  crystallization  as  those  lying  down,  as  the 
glaze  had  run  otf  to  a  great  extent.  However,  good  results  were 
obtained  on  two  small  vases  to  which  the  glaze  had  been  applied 
in  a  very  thick  coat,  though  here  also,  much  of  the  glaze  had  been 
lost. 


